Anchie, and Suz, thanks!
Anchie, the same jacket is very fluid on me. Roomy, but not oversized - which I don't wear unless it's a Summer linen shirt! The only reason I like the fit is because the jacket is SHORT and square. That part adds structure to my small frame. It's my usual Zara size, so I'm guessing this is the intended fit as Zara items typically fit me very well. Zara is also VERY on trend. Hence my preference for the M.
I personally preferred the other two Zara tweed jackets on you - (on your other thread) - because they were longer, and a better proportion to my eye. I also thought the blues were nicer with your hair and complexion.
All that said - YOU have to go with which jacket makes you happy. YOU are the wearer, and that is who you listen to